Method for manufacturing an encapsulated IC card having a molded frame and a circuit board

ABSTRACT

A method for manufacturing an integrated circuit card by providing a circuit board having electronic components mounted thereon intermediate the thickness of a molded frame and filling the frame with resin in a mold so that the resin passes through an opening in the circuit board and seals both sides of the board to a thickness no greater than the frame thickness.

This application is a division of application Ser. No. 07/526,849, filedMay 22, 1990, now U.S. Pat. No. 5,184,209.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an IC card and a manufacturing methodtherefor, the IC card being formed in such a manner that a circuit boardportion, on which electronic parts having various functions are mounted,is sealed in a frame with a molding resin sealant.

2. Description of the Related Art

FIGS. 1A and 1B are a plan view and a front elevational cross sectionalview each of which illustrates a conventional IC card of a non-contacttype having no electrode terminal for establishing an externalconnection. A circuit 3 is formed on one of the main surfaces of acircuit board 2 made of, for example, epoxy glass. Furthermore,electronic parts such as ICs (Integrated Circuits) 1 and communicationmeans (for example, a transmitting/receiving coil) (omitted from theillustration) are mounted on the same main surface of the circuit board2. The thus arranged circuit board 2 is adhered within a lower case 4aby using an adhesive, or the circuit board 2 and the lower case 4a arejoined by ultrasonic welding. Then, an upper case 4b is adhered onto thelower case 4a by using an adhesive so that an outer case 4 is formed.Thus, a thin IC card is manufactured.

FIGS. 2A and 2B are a front elevational cross sectional view and abottom view of another conventional IC card of a contact type arrangedin such a manner that electrode terminals for establishing an externalconnection appear on the surface thereof. A projecting terminal frame 2ais integrally formed with one of the surfaces of the circuit board 2 orfastened to the same by bonding. A circuit 3 is formed on the surface ofthe circuit board 2. A plurality of electrode terminals 5, are formed onthe outer surface of the terminal frame 2a, the plurality of electrodeterminals 5 being connected to the above-described circuit 3 via throughholes 6. The lower case 4a has an opening through which the terminalframe 2a is introduced so as to be engaged thereto. Thus, the circuitboard 2 is bonded onto the inside of the lower case 4a so that theelectrode terminals 5 appear outside on the surface of the IC card. Theupper case 4b is bonded onto the lower case 4a so that the outer case 4is formed. Thus, the IC card is manufactured.

The conventional IC cards of the above-described types are arranged insuch a manner that the thickness of each of the upper and the lowerplates of the outer case 4 and the gap between the components mounted onthe circuit board 2 are reduced in order to reduce the overall thicknessof the IC card. Therefore, a problem arises in that the IC card can beeasily deformed by external pressure, causing the electronic parts to besubjected to undesirable effects. Another problem arises in that it isdifficult to secure the circuit substrate 2 to the lower case 4a and tojoin the upper case 4b to the lower case 4a with an airtight sealbetween the periphery of the terminal frame 2a and the opening formed inthe lower case 4a (if there is a gap, water can enter therethrough).What is even worse, the upper case 4b and the lower case 4a which havebeen bonded to each other can be undesirably separated from each other.In order to prevent the deformation of the IC card due to externalpressure, means for injecting synthetic resin into the space in theouter case 4 must be provided.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to provide areliable, thin and compact IC card and a manufacturing method thereforin which a circuit board on which electronic parts, are reliablyhermetically sealed, so that the package can be easily formed anddeformation due to external force can be prevented.

In order to achieve the above-described object, according to the presentinvention, there is provided an IC card accommodating electronic partsand having a certain thickness, comprising: a frame made of moldedsynthetic resin and having a periphery having a width corresponding tothe thickness of the IC card and a circuit board integrally formed withthe periphery and disposed at an intermediate position in the directionof the thickness at the inner side of the periphery, the circuit boardhaving main surfaces; electric circuit means having a circuit formed onat least one of the main surfaces of the circuit board, at least oneelectronic part electrically connected to the circuit and mounted on theat least one of main surfaces of the circuit board and an I/O portiondisposed on the surface of either of the circuit board or the periphery,the I/O portion acting to supply/receive information to and fromexternal equipment; a resin sealant hermetically sealing the mainportion of the electric circuit means and having a thickness in a rangefrom the thickness of the periphery to a thickness which is slightlysmaller than the same, the resin sealant being injected into the frameso as to make the whole body a card-like shape; and means for forming anopening in the circuit board so that the resin sealant is moved from oneof the main surfaces of the circuit board to another main surface of thesame when the resin sealant is injected into the frame.

Another aspect of the present invention lies in an IC card accommodatingelectronic parts and having a certain thickness, comprising: a framemade of molded synthetic resin and having a periphery having a widthcorresponding to the thickness of the IC card and a board supportingportion integrally formed with the periphery and disposed at anintermediate position in the direction of the thickness at the innerside of the periphery, the board supporting portion being arranged toproject inwardly along the inner surface of the periphery; a circuitboard supported by the board supporting portion and having mainsurfaces; electric circuit means having a circuit formed on at least oneof the main surfaces of the circuit board, at least one electronic partelectrically connected to the circuit and mounted on at least one of themain surfaces of the circuit board and an I/O portion forsupplying/receiving information to and from external equipment; a resinsealant hermetically sealing the main portion of the electric circuitmeans and having a thickness in a range from the thickness of theperiphery to a thickness which is slightly smaller than the same, theresin sealant being injected into the frame so as to make the whole bodya card-like shape; and means for forming an opening with which the resinsealant can be moved from one of the main surfaces of the circuit boardto another main surface of the same when the resin sealant is injectedinto the frame.

Furthermore, the present invention includes methods for manufacturingthe above-described IC cards.

Other and further objects, features and advantages of the invention willbe described in the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a plan view and FIG. 1B is a cross sectional view each ofwhich illustrates a conventional non-contact type IC card;

FIGS. 2A is a cross sectional view and FIG. 2B is a plan view each ofwhich illustrates a conventional contact type IC card;

FIG. 3A is a plan view and FIG. 3B is a cross sectional view each ofwhich illustrates a non-contact type IC card according to a firstembodiment of the present invention;

FIG. 4A is a plan view and FIG. 4B is a cross sectional view each ofwhich illustrates the frame of the IC card shown in FIGS. 3A and 3B;

FIG. 5 is a cross sectional view which illustrates the frame of acontact type IC card according to a second embodiment of the presentinvention;

FIG. 6 is a cross sectional view which illustrates the frame of acontact type IC card according to a third embodiment of the presentinvention;

FIG. 7A is a plan view which illustrates the frame of a contact type ICcard according to a fourth embodiment of the present invention in astate in which resin sealant has not been injected and FIG. 7B is across sectional view which illustrates a state in which the IC card hasbeen completed;

FIG. 8 is a cross sectional view which illustrates an IC card accordingto a fifth embodiment of the present invention;

FIG. 9 is a cross sectional view which illustrates an IC card accordingto a sixth embodiment of the present invention;

FIG. 10 is a cross sectional view which illustrates an IC card accordingto a seventh embodiment of present invention;

FIG. 11A is a plan view and FIG. 11B is a cross sectional view each ofwhich illustrates a non-contact type IC card according to an eighthembodiment of the present invention;

FIGS. 12A is a plan view and FIG. 12B is a cross sectional view each ofwhich illustrates the frame of the IC card shown in FIGS. 11A and 11B;

FIG. 13 is a cross sectional view which illustrates a contact type ICcard according to a ninth embodiment of present invention;

FIG. 14 is a cross sectional view which illustrates a IC card accordingto a tenth embodiment of the present invention;

FIG. 15A is a plan view and FIG. 15B is a cross sectional view each ofwhich illustrates a frame of an IC card according to an eleventhembodiment of the present invention;

FIG. 16A is a plan view which illustrates a frame of an IC cardaccording to a twelfth embodiment of the present invention and FIG. 16Bis a cross sectional view which illustrates the completed IC card;

FIG. 17A is a plan view and FIG. 17B is a cross sectional view each ofwhich illustrates a frame of an IC card according to a thirteenthembodiment of the present invention; and

FIG. 18 is a cross sectional view which illustrates a frame of an ICcard according to a fourteenth embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 3A is a plan view and FIG. 3B is a cross sectional view each ofwhich illustrates an IC card according to a first embodiment of thepresent invention. Referring to the drawings, a frame 11 is made of asynthetic resin such as thermotropic liquid crystal polymer manufacturedby injection molding, the frame 11 being arranged to be in the form of ashape as shown in FIGS. 4A and 4B. The frame 11 has a peripheral portion11a, a circuit board 11b integrally formed at an intermediate positionrelative to the thickness direction of the frame 11 and an opening 11cformed therein for the purpose of communication between the two sides ofthe circuit board 11b.

Reference numeral 12 represents the position of a gate portion throughwhich resin is injected into the cavity of a mold which molds theabove-described frame 11. In order to cover the mark on the resin fromthe gate portion, the above-described position at which the gate portionis disposed is arranged at a position adjacent to the inner surface ofthe periphery portion 11a of the circuit board 11b.

A circuit 13 is formed on the surface of the circuit board 11b of theabove-described frame 11 by electroless plating, etching means orelectrolytic plating.

Referring back to FIGS. 3A and 3B, the function parts, that is theelectronic parts such as ICs 1 of the IC card are mounted on the surfaceof the board 11 on which the circuit 13 is formed. Since this IC card isa non-contact type having no electrode terminals, communication meansformed by a coil or the like, that is an I/O portion (omitted from theillustration) is also mounted on the same surface of the circuit board11b.

Then, the frame 11 is placed in the mold and the peripheral portion 11ais fitted within the cavity (omitted from the illustration) of the mold.The thermotropic liquid crystal polymer, which is the same material asthe frame 11, is used as the resin injected in the frame

Thus, the electronic parts, the circuit and the I/O portion(collectively called "function parts" hereinafter) are embedded so thata resin package 14 is formed integrally with the frame 11. The surfaceof the resin package 14 is made flat and reaches a level which isslightly lower than the level of the two sides of the peripheral portion11a. As a result, the introduction of the resin into the outer surfacesof the peripheral portion 11a of the frame 11 at the time of molding theresin package 14 is prevented. Furthermore, the above-described low flatsurface of the resin package 14 can be used as a surface on which anillustration is written or to which a seal or a panel is bonded.

FIG. 5 is a cross sectional view which illustrates a second embodimentof the present invention, where a contact type IC card, the electrodeterminal of which appears on the surface of the IC card, is shown.According to this embodiment, an electrode terminal 15 connected to thecircuit 13 of the circuit board 11b of the frame 11 is formed on the topsurface of a portion 11d of the periphery portion 11a and arranged toappear outside. At least two position reference holes 16 are formed atpositions so as not to appear on the surface of the IC card and close tothe portion 11d of the periphery portion 11a so as to serve as apositional reference when the circuit 13 and the electrode terminal 15are formed, the above-described at least two position reference holes 16being formed at the time of molding the frame 11. As a result, theelectrode terminal 15 can be accurately positioned with respect to theoutline of the IC card.

FIG. 6 is a cross sectional view which illustrates a frame according toa third embodiment of the present invention. In order to positionallyaccurately form the circuit 13 and the electrode terminal 15, at leasttwo positioning pin portions 17 which project from the circuit board 11bare formed. The height of each of the pin portions 17 is arranged not toreach the surface of the IC card.

FIG. 7A is a plan view which illustrates the frame in a state whereresin has not been injected so as to form the resin package of the ICcard according to a fourth embodiment of the present invention. FIG. 7Bis a cross sectional view which illustrates the same in a state wherethe IC card has been completed. According to this embodiment, at leasttwo positioning holes 18 for positionally accurately forming the circuit13 and the electrode terminal 15 are formed in the circuit board 11b.According to this embodiment, one IC 1 is mounted on the circuit board11b.

FIG. 8 is a cross sectional view which illustrates an IC card accordingto a fifth embodiment of the present invention. This embodiment can besuitably applied to an IC card of the type which includes an EPROM IC 1that must have a transparent portion. According to this embodiment, atransparent resin portion 19, made of, for example,tetramethylmonopentene (TPX) resin, is formed on the surface of theEPROM IC 1 mounted on the surface of the circuit board 11b. The topsurface of the transparent resin portion 19 is arranged to appear on thesurface of the IC card.

FIG. 9 is a cross sectional view which illustrates an IC card accordingto a sixth embodiment of the present invention. According to thisembodiment, the EPROM IC 1, which is one of the function parts mountedon the circuit board 11b, has a transparent window 20. The moldedresin-package 14 has an opening 14 formed on the transparent window 20so that the opening 14 appears outside. A seal such as an aluminum foilis applied to the opening 14a so as to prevent the transmission ofultraviolet rays into the cases except when contents of the memory ofthe EPROM are reloaded.

FIG. 10 is a cross sectional view which illustrates an IC card accordingto a seventh embodiment of the present invention. A resin package 21made of thermotropic liquid crystal polymer is formed by molding in thelower half portion of the frame 11 in which the function parts 1 such asthe ICs 1 are mounted on the circuit board 11b. On the other hand, atransparent resin package 22 made of acrylic resin or the like is formedin the upper portion of the same by molding. As a result, the functionportion of the IC card can be seen through the transparent resin package22.

According to the above-described embodiments, the circuit board 11b isintegrally formed in the frame 11. Next, other embodiments in each ofwhich an independent circuit board is supported within the frame will bedescribed.

FIGS. 11A and 11B are a plan view and a cross sectional view whichrespectively illustrate an IC card according to an eighth embodiment ofthe present invention. Referring to the drawings, a frame 23 ismanufactured by injecting, for example, thermotropic liquid crystalpolymer, the frame 23 being arranged to be in the form of a shape asshown in FIGS. 12A and 12B. That is, the frame 23 has a peripheralportion 23a and a board supporting portion 23b projecting inwards overthe periphery portion 23a, the board supporting portion 23b beingdisposed in the intermediate position in the direction of the thicknessof the peripheral portion 23a.

Referring back to FIGS. 11A and 11B, a circuit 25 is formed on the mainsurface of the circuit board 24 supported on the board supportingportion 23b in the frame 23. In addition, the ICs 1 and other functionparts are mounted on the same surface of the circuit board 23. Sincethis IC card is a non-contact type having no electrode terminal,communication means formed by a coil or the like, that is the I/Oportion (omitted from illustration) is also mounted on the same surfaceof the circuit board 23. The circuit board 24 has an opening 24a for thepurpose of introducing injected resin.

Then, the frame 23 is placed in the mold and a peripheral portion 24a isfitted within the cavity (omitted from the illustration) of the mold.The thermotropic liquid crystal polymer, which is the same material asthe frame 23, is used as the resin to be injected in the frame 23. Thus,the circuit board 24 is embedded in the frame 23 so that the resinpackage 14 is formed integrally with the frame 23. The two sides of theresin package 14 have the same level as the two sides of the peripheralportion 23a or are slightly lower with respect to the same.

FIG. 13 is a cross sectional view which illustrates an IC card accordingto a ninth embodiment of the present invention where a so-called contacttype IC card, the electrode terminal of which appears outside, is shown.The circuit substrate 26 has circuits 25 formed on two sides thereof andan opening 26a formed therein. A terminal frame 26b is integrally formedor bonded to an end portion of the circuit board 26. The terminal frame26b has, on the outer surface thereof, a plurality of electrodeterminals 27 which appear outside. The electrode terminals 27 areconnected to the corresponding circuits 25 by virtue of correspondingthrough holes 28. The resin package 14 is formed in the frame 23 byinjection molding so that the circuit board 26 is embedded and sealed.Furthermore, the electrode terminal 27 appears on the top surface of theframe 23.

FIG. 14 is a cross sectional view which illustrates an IC card accordingto a tenth embodiment of the present invention. According to thisembodiment, a terminal electrode 27 appears on the lower side of the ICcard in a contrary manner to the structure according to the IC cardshown in FIG. 13.

FIGS. 15A and 15B are a plan view and a front elevational crosssectional view which illustrate the frame of an IC card according to aneleventh embodiment of the present invention. According to thisembodiment, the length of the circuit board is arranged to be short withrespect to the inner length of the frame. A frame 29 made of syntheticresin has a board supporting portion 29b disposed inside a peripheryportion 29a thereof. Furthermore, a sub-supporting portion 29c extendingin the widthwise direction is formed intermediate of the length of theframe. A conical supporting portion 29d is integrally formed below thesub-supporting portion 29c, the conical supporting portion 29d havingthe front end portion of the conical shape which is positioned at thesame level as the level of the lower surface of the periphery portion29a. As a result, the area of the supporting portion 29d which appearson the outer surface of the completed IC card can be reduced. Thus, whenthe frame 29 in which the circuit board 26 is supported by the boardsupporting portion 29b is placed in the mold, an end portion of thecircuit board 26 is supported by the sub-supporting portion 29c and thesupporting portion 29d.

The resin injected into the frame 29 placed in the mold passes through alarge gap formed between an end portion of the circuit board 26 and theboard supporting portion 29b. Thus, the resin is introduced into the twosides of the circuit board 26, causing the IC card to be molded.

FIGS. 16A and 16B illustrate a twelfth embodiment of the presentinvention including a sub-supporting portion of the structure which isdifferent from that of the sub-supporting portion 29c of the frame 29shown in FIGS. 15A and 15B. FIGS. 16A and 16B are a plan view of theframe and a cross sectional view of the IC card, respectively. Referringto the drawings, the frame 29 has three sub-supporting portions 29e inan elongated shape formed therein from the board supporting portion 26binside the periphery portion 29a toward the central portion thereof.Each of the three sub-supporting portions 29e has an integrally formedconical supporting portion 29f at the front end portion thereof. Thecentral sub-supporting portion 29e of the three sub-supporting portions29e has the supporting portion 29f disposed in the upper portion of theframe 29, while the other two sub-supporting portions 29e have thesupporting portions 29f disposed in the lower portion of the frame 29.When the frame 29, in which the circuit board 26 is received by theboard supporting portion 29b, is placed in the mold, each of thesub-supporting portions 29e and the supporting portion 29f hold an endportion of the circuit board 26 therebetween.

As shown in FIG. 16B, the height of each of the supporting portions 29fis arranged such that the function parts disposed on the board 26 do notappear in the resin package 14 and that the front end portion of each ofthe supporting portions 29f does not project over the outer surface ofthe resin package 14.

FIGS. 17A and 17B are a plan view and a front elevational crosssectional view which illustrate the frame according to a thirteenthembodiment of the present invention. The board supporting portion 23bformed inside the periphery portion 23a of the frame 23 has a pair ofpositioning pins 30 integrally formed on the two sides of the boardsupporting portion 23b. As a result, positioning holes (omitted from theillustration) formed in the circuit board 26 can be engaged to theabove-described positioning pins 30. Therefore, the outline of the frame23 and the circuit board 26 can be accurately positioned with respect toeach other. The above-described accurate positional relationship is acritical factor when an IC card, the electrode terminal of which appearsoutside, is designed.

FIG. 18 is a front elevational cross sectional view which illustrates aframe according to a fourteenth embodiment of the present invention. Theboard supporting portion 23b of the frame 23 has a pair of positioningholes 31 formed on the two sides of the board supporting portion 23b. Asa result, positioning pins (omitted from the illustration) formed in thecircuit board 26 can be engaged to the above-described positioning holes31. Therefore, the outline of the frame 23 and the circuit board 26 canbe accurately positioned with respect to each other.

According to the above-described embodiments, thermotropic liquidcrystal polymer is employed as the synthetic resin to form the frame andalso to be injected into the frame so as to integrally mold the resinpackage The present invention is not limited to the above-describeddescription. For example, polycarbonate resin or polybutyleneterephthalate (PBT) resin may be employed solely or in the form of amixture with other components.

Although any thermal plastic and thermal setting synthetic resin whichcan be usually used for molding can be employed, it is preferable thatheat resistant and thermal plastic synthetic resin be employed and thethus employed resin be injection-molded in order to easily mount theparts such as the ICs 1 and to improve the manufacturing yield.

Although the TPX resin exhibiting an excellent ultraviolet raypermeability is employed as the transparent resin, the present inventionis not limited to the above-described description.

As described above, according to the present invention, the structure isarranged in such a manner that the circuit board is integrally formed atan intermediate position in the thickness direction of a frame made ofthe synthetic resin and inside the periphery of the frame. Furthermore,the circuit is formed on the circuit board and the function parts aremounted on the same, and then the synthetic resin is injected in theframe so that the IC card is formed. Therefore, a package in which thefunction part portion can be reliably hermetically sealed can be easilyobtained. The package thus obtained exhibits satisfactory deformationresistance against external forces, excellent durability andreliability.

According to another aspect of the present invention, the boardsupporting portion is disposed at an intermediate position in thedirection of the thickness of the frame made of the synthetic resin andon the inside of this frame. Furthermore, the circuit board, on whichthe circuit is formed and the electronic parts are mounted, is supportedon the board supporting portion, and then the synthetic resin isinjected in the frame so that the IC card is formed. Therefore, thepackage in which the function part portion can be reliably hermeticallysealed can be easily obtained. The package thus obtained exhibitssatisfactory deformation resistance against external force, excellentdurability and reliability.

Although the present invention has been described in its preferred form,it is understood that the present disclosure of the preferredembodiments may be changed in construction or the combination andarrangement of parts may be changed without departing from the spiritand the scope of the present invention as hereinafter claimed.

What is claimed is:
 1. A method of manufacturing an IC cardcomprising:injecting a synthetic resin into a mold so that a frame isformed, said frame integrally comprising a periphery having a thicknesscorresponding to the thickness of said IC card and a circuit boarddisposed intermediate the thickness of said frame and having opposedfirst and second surfaces and an opening penetrating from said firstsurface to said second surface; forming a circuit, electronic parts, andan I/O portion on at least one of said first and second surfaces of saidcircuit board; and filling said frame with synthetic resin in a moldpassing through said opening to said first and second surfaces of saidcircuit board to hermetically seal said circuit, electronic parts, andI/O portion with a thickness no greater than the thickness of saidframe;
 2. A method of manufacturing an IC card comprising:injecting asynthetic resin into a mold so that a frame is formed, said frameintegrally comprising a periphery having a thickness corresponding tothe thickness of said IC card and a circuit board supporting portiondisposed intermediate the thickness of said periphery within said frame;forming a circuit, electronic parts, and an I/O portion on at least oneof opposed first and second surfaces of said circuit board and anopening which penetrates from the first surface to the second surface;and filling said frame with synthetic resin in a mold with saidsynthetic resin passing through said opening to hermetically seal saidcircuit, electronic parts, and I/O portion with a thickness no greaterthan the thickness of said frame.